Catch Can - Valve Pictures at 54k mi

[WingsAA]

Hey guys. I wanted to share some information on the beloved catch can topic... nothing scientific just a real-world sample.
So I put an Elite Engineering E2-X catch can on my 2016 L86 Yukon XL Denali when I bought it new... can went on around 300miles in. I did not install the clean side separator. I used Mobil1 0w20 Annual Performance and M1-113A filter... changed the oil and filter every 4k miles (don't flame me for wasting money). I've recently switched over to Amsoil Signature full synthetic 0w20 and Amsoil filter as well. Should also note, I've been running a tune and have had DOD disabled from day 1.

Okay, details out of the way, I took my intake manifold off this past weekend as the curiosity got the best of me and I wanted to see what the valves looked like. Behold the results. Note, the valves got cleaner as you worked you way to the rear of the engine. I should confirm, I'm right at 54,500 miles. Curious what you all think. Just wanted to share this use case from a vehicle that has basically had a can on it from the start as the only owner. I was pretty tired from the gymnastics session in and out of the engine bay so apologies the pictures aren't professional. was having trouble holding a light, my phone and not end up falling out on to the garage floor

 

[WingsAA]

 

[ivin74]

I did the same experiment on the first catch can I bought and had similar results as you. I have then changed out the catch can to the RacerX catch can with an oil separator and hope to get better results.

 

[Dantheman1540]

Love seeing tests with real-world results like this. I'm surprised It's so dirty in there, especially with such a nice can.

 

[Larryjb]

I'd be curious to see what the valves looked like on a similar vintage and mileage without a catch can.

This is one reason Ford introduced two sets of injectors on their Ecoboost, one set for direct injection, the other before the valves. One of the main reasons for this is that there is no safe way to clean the valves on an Ecoboost without tearing the engine apart. At least on ours we can run some cleaner through the intake to clean that stuff up if necessary.

 

[Fifty]

The 2018 DI v6 has a built in catch can. The 2015-2017 did not and the oil problem was bad.

I wonder if the newer 5.3 and 6.2 got a built in catch can?

it’s in the valley on the v6.

I need to install my catch can on my 2015 but I want to get the valves and intake ports blasted and cleaned first

 

[Larryjb]

I wonder if the 2018 DI V6 "catch can" really keeps valves cleaner. It might, but I think it would be for a different reason. The valley is going to be hot and not let much oil vapour condense like the external catch can will. It's almost like GM wants the oil vapour to remain hot so that it does not condense until it gets to the combustion chamber where it will be burned and the remaining hydrocarbons cleaned up by the catalytic converter.

 

[Fifty]

The interesting thing was that the engineers that came onto the Colorado forums made a point to call it an “air oil separator” and making an aftermarket aos not needed.

I have not taken it apart, and faintly remember seeing the engineering drawings and it looking like it would work.
But until I pop the intake manifold or stick a long camera in, who knows

 

[Fifty]

https://gmauthority.com/blog/2019/01/gm-patents-innovative-new-integrated-oil-separator-assembly/

 

[Fifty]

https://www.coloradofans.com/threads/gm-12668439-separator-asm-pcv-oil.398611/

This guys put a aos on his truck and it collected nothing. So he bought the factory aos pet to check it out.

 

[Prospect62]

Man I just put mine on at 66,000 miles and I'm starting to wonder if it was even worth it...those are DIRTY!

 

[sd172]

It will be interesting look at mine and see if running E85 and WOT pulls help to keep the valves clean (lower soot levels?). I might upgrade to the ported 6.2 intake, throttle body and air box.

 

[WingsAA]

I should add... I'm running flex fuel also. Regardless, there's no fuel being sprayed on the back sides of the valves so really no difference from gas at the end of the day... other than your injectors being cleaner.

 

[sd172]

Thank you, this info is very helpful. Do you know if Gen 5 engines have misfire codes / other issues related to the carbon deposits or it’s mostly cosmetics?

 

[WingsAA]

It's definitely not cosmetic and the issue is real. I do plan to clean my valves at some point in the near future as I plan to keep the vehicle. I should clarify, I do not have any drivability issues and she still runs really smooth and gas mileage is still good. If the carbon deposits get bad enough then yes, you'll have codes and drivability issues, etc.

I tend to keep vehicles longer and perform above the required maintenance to try and get the most life out of them. If you're leasing or don't plan to keep a vehicle for an extended period of time then don't worry about any of this and drive it like you stole it. lol

 

[sd172]

I would like to keep mine for a while, too. I would request a manual port clean when the high pressure fuel pump needs replacement.

 

[WingsAA]

I would like to keep mine for a while, too. I would request a manual port clean when the high pressure fuel pump needs replacement.

Let me know if you need any tips or tricks on getting the manifold off when you decide to do so. It's really not that difficult but slow and steady is key... even with getting the harness removed from the back of the manifold cover shield. The biggest frustration I had was how I felt the next day from lying across the engine bay. It sucks that my brain still thinks I'm in my 20's Gearhead for life!

 

[89Suburban]

I am amazed how much oil is on those valves.

 

[sd172]

Thank you kindly, I will reach out to you if I need more info.
Offtop question. What kind of mileage are you getting with ethanol? I get 11 on full E85 and 12-13 on E50, my average speed in town is around 25 mph.

 

[WingsAA]

Thank you kindly, I will reach out to you if I need more info.
Offtop question. What kind of mileage are you getting with ethanol? I get 11 on full E85 and 12-13 on E50, my average speed in town is around 25 mph.

Yikes, that's a tough one to answer. Partly because you're going to get less mileage out of Ethanol just due to the fact that you need more of it. Drawing from memory I think the base figures range on 15% to 25% fewer mpg than when running gas. That varies on ethanol content which can range from 51% to 85% at the pump. The other factor is it's more fun to get into the throttle it so there's that as well. I've been getting consistent 75% ethanol content at a flex fuel station (Kroger) near me which seems to be the best. Most others are closer to 52% and inconsistent in my area.

End of the day... you realistically need to calculate dollars/gallon vs miles/gallon to determine if it's worth it.

To answer the question specifically related to 93 octane gas, I recently drove from Dallas, TX to Columbus, OH and I got 22mpg on that trip running 93 with two passengers. Second trip I pulled a 23ft Airstream and got a whopping 5mpg
In and around Dallas when I was commuting more pre-Covid, I get around 12-15mpg running 93.

I don't really track E85

Seems like you're probably in the ballpark with those numbers.